Although there is as yet no coverage of this subject in the articles and booksdealing with the fragmentation of former Yugoslavia, the transformation ofthe Yugoslav People's Army (JNA) into an army protecting Serbian interestsis perceived as commonplace. This article examines the causes behind andthe course of this issue. The transformation of the JNA was not continuous,but was a consequence of several factors, including back-room politics, thearmy generals' conservatism towards the political changes in Yugoslavia,the anti-army, anti-Yugoslav and anti-Communist sentiments in Sloveniaand Croatia, and the ethnic constitution of the JNA. To examine thebehaviour of Yugoslav People Army during the brake-up of the Yugoslavstate, the author focuses on both ideological and socio-economic factorsand the political evolution in the 1980's and early 1990's.